1. Field of the Invention
The present invention relates to a syringe, and more particularly to a safety syringe that can safely hold a used needle and prevent the syringe from being used more than once.
2. Description of Related Art
A conventional syringe has a hollow barrel, a plunger and a needle hub. The needle hubs of conventional syringes are easily inclined during use so the needle hubs are difficult to retract into the barrel. Due to contagious diseases, the needles of syringes and even the hollow barrels and plungers, should not be used again and should be discarded immediately after use. Also, to keep nurses, doctors or workers who deal with discarded syringes from getting injured or infected by used needles, a safety syringe is needed. The conventional safety syringe often has a complex structure, so to provide a simple and effective safe design for the needles of syringes is still needed.
To overcome the shortcomings of conventional syringes, the present invention provides a safety syringe to mitigate or obviate the aforementioned problem.
The primary objective of the present invention is to provide a safety syringe that has a simpler structure than the conventional safety syringe and improves safety. The safety syringe in accordance with the present invention comprises a hollow barrel, a plunger, a tube and a needle hub.
The hollow barrel has a proximal open end, a distal closed end, an outside surface, a dovetail keyway and a first through hole. The plunger is slidably mounted inside the hollow barrel. The tube has a proximal open end and a distal open end and is mounted on the hollow barrel. The needle hub and the spring are mounted inside the tube, and the needle selectively extends from the proximal open end of the tube. The first through hole is defined in the hollow barrel through the dovetail keyway, and a second through hole is defined in the tube. The first through hole faces the second through hole.
When using the safety syringe, the needle hub extends out of the tube to draw a blood sample. When finishing taking a blood sample, the used needle hub is retracted inside the tube to keep the used needle from injuring or infecting a person.
Other objectives, advantages and novel features of the invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings.